Pump construction for hand-operated dispenser



Dec. 14, 1965 A. J. KEENEY ETAL 3,223,292

PUMP CONSTRUCTION FOR HAND-OPERATED DISPENSER Filed Sept. 30, 1964 INVENTOR Allen J. \4 Laney Wo'L SteLman HGEN United States Patent 3,223,292 PUMP CSNSTRUCTION FOR HAND-OPERATED DISPENSER Allen I. Keeney, Huntington, and Wolf Steiman, Fairfieid, Conn, assignors to Valve Corporation of America, Bridgeport, Conn, a corporation of Delaware Filed Sept. 30, 1964, Ser. No. 400,350 4 Claims. (Cl. 222321) This invention relates to small hand-held dispensers of the pump type, and more particularly to the cylinder and piston constructions of such devices.

The invention concerns improvements in the dispenser pump of copending application Serial No. 278,962 filed May 8, 1963, now Patent No. 3,159,316 of Nov. 1, 1964, and entitled Atomizer Pump, owned by the assignee of the present application.

In this prior filed application there is disclosed and claimed a pump construction wherein the piston comprises a molded rubber or rubber-like member having a pair of coaxial flexible skirt or piston elements carried by a common elongate upwardly extending hollow shank. The piston elements are spaced apart and normally straddle a vent opening in the side wall of the cylinder, such opening being uncovered when the piston is depressed, thereby to enable external air to come into the container for replacement of the liquid being discharged.

The double piston element of this prior application is highly efi ective in its operation, preventing leakage of liquid past the skirt portions and providing a smooth pumping action. However, the use of rubber or rubberlike composition may be a disadvantage under certain circumstances of use, and the cost of molding such a piston assemblage is comparatively high due to the somewhat complicated shape involved. Also, the use of rubber increases the friction of the piston on the cylinder walls, making necessary a slightly greater operating or depressing force required of the user.

The above considerations of this prior pump con struction are bettered by the present invention, and one object of the invention is to provide an improved cylinder and piston construction for a hand-operated dispenser pump, wherein the fabrication is simplified and made less costly, and wherein frictional forces are reduced while at the same time a high degree of efficiency is retained in the pumping of the liquid and in preventing leakage of liquid past the skirt portions of the multiskirt piston assemblage.

Another object of the invention is to provide an improved cylinder and piston assemblage as above set forth, which is rug ed in construction and reliable in operation over an extended period of use.

A feature of the invention resides in the provision of an improved multi-part piston assemblage for a pump, wherein the assembly of the parts is quickly and easily effected, and wherein the assembled parts are retained in their relative operative positions by the existing return coil spring of the pump.

Another feature of the invention resides in the pro vision of a multi-part piston assemblage as above outlined, wherein a sturdy and substantially unyielding, simple abutment means is provided for one end of the piston return spring, said abutment means constituting a part of one of the piston skirt members.

Other features and advantages will hereinafter appear.

In the drawings accompanying this specification, similar characters of reference are used to designate like components throughout the several views, in which:

FIG. 1 is a side elevational view of a small spray dispenser having the improved pump structure as provided by the invention.

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FIG. 2 is an axial sectional view of the pump construction of the dispenser, revealing the operative parts. The piston assemblage is shown in the raised, non-spraying position.

'FIG. 3 is a view like FIG. 2 but showing the piston assemblage in the depressed position after having gone through a downward, spraying movement.

Referring first to FIG. 1, the dispenser shown therein comprises a container 1% of any conventional type, having mounted in its neck a dispensing pump structure 12 including a depress button or spray head 14 having a discharge orifice 16. Within the container 10 there is a dip tube 18, connected with the lower portion or end of the pump cylinder 20.

As seen in FIGS. 2 and 3, the cylinder 20 is tubular, with a reducedaliameter depending or bottom inlet portion 22 to which there is aifixed the dip tube 13. In the portion 22 an annular seat is provided for a ball check valve 24.

The upper end of the cylinder 20 has an outturned flange 26 engaged with an annular sealing ring 28 which rests on the rim portion 30 of the container 10. The assemblage of flange 26 and sealing ring 23 is secured to the container rim 30 by an inverted mounting cup structure 32 having its lower edge portion 34 crimped under a shoulder 36 of the container. The mounting cup 32 has a central opening which is slightly smaller in diameter than the bore of the cylinder 20 and through which there passes the hollow stem 38 of the plunger assemblage.

On the upper portion of the stem 38 the spray head 14 is mounted, said upper portion also having an annular valve seat in which there is carried a back-check ball valve 40.

Intermediate the ends of the shank 38 of the plunger there is an internal annular valve seat 42 arranged for engagement by a valve head 44 on a small-diameter stem 46, the latter being joined to a large-diameter stem portion 48 provided with a base enlargement 5% testing on an internal shoulder 52 at the lower portion of the cylinder 20. A helical compression coil spring 54 engages the base enlargement 50 of the stem portion 48 and also en gages the piston assemblage of the pump, thereby to maintain the stem 46, 48 and the valve head 44 stationary with respect to the cylinder 20 and container 10.

In accordance with this invention, the piston assemblage, designated generally by the numeral 56, is constituted in a novel and unique manner to provide the maximum degree of effectivenes and simplicity of construction, and low fabrication cost. This novel piston assemblage comprises an upper depending skirt member 58 which is preferably integral with the plunger stem 33, and a lower skirt member 60 which is constituted as a piece separate from the upper skirt 58 and which interfits with and is supported by the upper skirt 58 so as to move therewith during the reciprocation of the plunger. Further, the lower skirt 69 is arranged to be engaged by the plunger return spring 54 and to transmit the force of said spring -to the plunger shank 38 whereby the plunger is normally retained in the raised, non-discharging position shown in FIG. 2.

A side vent opening 21 in the cylinder 20 permits ingress of air when the plunger assemblage is in the depressed position of FIG. 3.

The piston skirts 58, 60 are preferably slightly flared as shown, whereby when removed from the cylinder 20 they are slightly larger at their greatest diameter than the bore of the cylinder. The plunger stem 38 and its skirt 58, as well as the lower skirt 50 are preferably molded of resilient plastic substance such as polyethylene or similar formulations.

The lower skirt 6%} ha a shank or mounting portion 62 of tapered configuration, terminating at its top in a substantially cylindrical bushing 64 which is frictionally received in a cylindrical recess or socket 66 of the lower portion of the shank 38.

By virtue of the press-fit of the bushing 64 in the socket 645 and the action of the return spring 541, the lower piston skirt 60 of the assemblage will be retained in the operative position shown in FIGS. 2 and 3 with respect to the upper skirt 58 and shank portion 38 of the plunger.

Also, by virtue of the two-piece construction of the piston comprising the parts 58, 60 the molding and fabrication of these may be economically carried out without involving complicated mold configurations or diflicult stripping operations. Moreover, inasmuch as the skirt portions 58, 6d are fabricated of plastic substance the matter of stripping these from a mold if they were to be molded as a single piece, would involve considerable difficulty and result in deformation of the parts, to such an extent that their usefulness would be questionable. Forming the skirts 58, 60 of polyethylene plastic is less costly than if the parts were molded in one piece of rubber or rubber-like substance, and a greater uniformity is had by use of the two-piece construction, with a smoother more friction-free action of the plunger than if the skirts were of molded rubber composition. The slippery surfaces of the polyethylene skirts 58, 60 in conjunction with the slippery surface of the bore of the molded polyethylene cylinder 29 eliminate sticking in the operation of the plunger while at the same time insuring an effective, leakproof piston and cylinder or pump assemblage.

The use of the two separate skirts 58, 60 of molded plastic substance provides a more effective piston device than if a single molded plastic piston member were employed, having a length equal to the combined length of the individual skirts 58, 60. This is because the two separate skirts provided have freedom and resilience, as regards engaging the bore of the cylinder 20 to effect a liquid-tight yet freely slidable coaction therewith. As understood at present, the presence of the free rims of the two skirts 58, 60 provides for less leakage with smaller forces existing between the piston and cylinder, resulting in a more effective and smoother acting pump assemblage. The reduced friction of the molded plastic components, as compared with molded plastic rubber, makes for an easier action of the piston and pump, as well.

The two-piece plastic piston assemblage as thus provided above gives an improved result in that there is less leakage, less friction, a smoother action, and more uniformity as compared with one piece constructions of plastic substance or double skirt pistons molded in one piece of rubber or rubber-like composition. The pump construction is seen to be simple, economical to fabricate and easy to assemble, as Well as providing for a superior performance.

Variations and modifications may be made within the scope of the claims, and portions of the improvements may be used without others.

We claim:

*1. In a hand-operated dispenser, a pump construction comprising, in combination:

(a) a cylinder,

(b) a pair of nested and assembled upper and lower piston cups in a cylinder, both facing in the same direction and each cup constituting a molded resilient plastic piece separate from the other, said cups being closely spaced,

(c) a piston stem on which the cups are mounted, said stem passing out through one end of the cylinder,

(d) means providing a discharge passage through said piston cups and piston stem, and

(e) means maintaining the piston cups in assembled relation.

2. The invention as defined in claim 1, wherein:

(a) the upper piston cup and piston stem are molded as a single integral piece of resilient plastic substance,

(b) said lower piston cup having a shank at its top,

(c) said piston stem having a socket in which the shank of the cup is received,

3. The invention as defined in claim 2, wherein:

(a) a piston return spring is provided in the cylinder, engaging the lower cup and maintaining the latter in assernlbled position nested in the upper cup.

4. The invention as defined in claim 3, wherein:

(a) the shank of the lower piston cup has a substantially frusto-conical portion the large end of which is connected to the cup side walls,

(b) said spring engaging the large end of the frustoconical shank portion,

(c) said shank portion constituting a substantially unyielding abutment for said spring, preventing spreading of the cup side walls.

References Cited by the Examiner UNITED STATES PATENTS 3,064,865 11/1962 Scoggin et al 222-325 LOUIS J. DEMBO, Primary Examiner. 

1. IN A HAND-OPERATED DISPENSER, A PUMP CONSTRUCTION COMPRISING, IN COMBINATION: (A) A CYLINDER, (B) A PAIR OF NESTED AND ASSEMBLED UPPER AND LOWER PISTON CUPS IN A CYLINDER, BOTH FACING IN THE SAME DIRECTION AND EACH CUP CONSTITUTING A MOLDED RESILIENT PLASTIC PIECE SEPARATE FROM THE OTHER, SAID CUPS BEING CLOSELY SPACED, (C) A PISTON STEM ON WHICH THE CUPS ARE MOUNTED, SAID STEM PASSING OUT THROUGH ONE END OF THE CYLINDER, (D) MEANS PROVIDING A DISCHARAGE PASSAGE THROUGH SAID PISTON CUPS AND PISTON STEM, AND (E) MEANS MAINTAINING THE PISTON CUPS IN ASSEMBLED RELATION. 